Brain Embedding Medium

GLENN HOLM karuzis at
Sat Dec 7 16:35:00 EST 1991

In article <531 at>, tbd at (Tristan Davies) writes...
>In article <16NOV199120460769 at> karuzis at (GLENN HOLM) writes:
>-->Anyone out there have suggestions for the ideal embedding medium to surround
>-->small, fragile brain specimens prior to cutting on vibratome or freezing
>You left out a couple of details:
>1.  Is the tissue you're cutting fixed? with what?
>2. How thick do you want your sections?
>3. Are you only using them for immunocytochemistry?
>OK, three details that I can think of.
>I don't know of other techniques, but I wouldn't dismiss the ones you've 
>already tried yet.  I've had good luck cutting 15-20 um and thicker Vibratome 
>sections from brains embedded in  albumin/gelatin.  
>I think cryostat sections are the gold standard for immunostaining, and 

Basically, brains are fixed by perfusion or immersion in 4% paraformaldehyde.
It's newborn or fetal rat or mouse that's the real problem- fragility and
"stickiness" of the brains makes them difficult to handle for 
immunohistochemistry.  Also brain slices of bout 200 um need to be cut down
to ca. 20 um - would be easier embedded since there would be more to work 
with.  We find immuno "on slide" after cryostat cutting not as good as that
done on free floating sections.  

Recently have been fooling with low melting point agarose in concentrations
of 2-3% on vibratome.  Medium seems a little too firm to get uniform sections-
compression of block causes thick and thin.  Have not yet tried 
albumin/gelatin on vibratome - is it the old standard recipe, hardened with

I'll report back on future progress.  Thanks for the responses.
|Glenn Holm                         Internet:karuzis at|
|M.I.T Dept. of Brain + Cog. Sci.   Bitnet:karuzis at mitwccf       |
|Cambridge, MA 02139       "Real Neuroscientists don't do gels!" |

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